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<head><meta charset="utf-8"><title>Target feature level chatter · project-portable-simd · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/index.html">project-portable-simd</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html">Target feature level chatter</a></h3>

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<a name="227035953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227035953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227035953">(Feb 19 2021 at 22:04)</a>:</h4>
<blockquote>
<p>x86-64: CMOV, CMPXCHG8B, FPU, FXSR, MMX, FXSR, SCE, SSE, SSE2<br>
   x86-64-v2: (close to Nehalem) CMPXCHG16B, LAHF-SAHF, POPCNT, SSE3, SSE4.1, SSE4.2, SSSE3<br>
   x86-64-v3: (close to Haswell) AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, XSAVE<br>
   x86-64-v4: AVX512F, AVX512BW, AVX512CD, AVX512DQ, AVX512VL</p>
</blockquote>
<p>These are the proposed target feature levels. Seems about right?<br>
AMD implemented POPCNT and LZCNT as one set, but Intel deferred LZCNT into part of BMI1.</p>



<a name="227036253"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227036253" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227036253">(Feb 19 2021 at 22:06)</a>:</h4>
<p>Yep</p>



<a name="227037227"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227037227" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Thom Chiovoloni <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227037227">(Feb 19 2021 at 22:11)</a>:</h4>
<p>oh, it's not this groups problem but i wonder if this gives us a path forward to stabilizing AtomicU128 <em>somewhere</em></p>



<a name="227037917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227037917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227037917">(Feb 19 2021 at 22:13)</a>:</h4>
<p>Never even thought of that, do any architectures actually have 128-bit atomics or do they all need fences?</p>



<a name="227038127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038127">(Feb 19 2021 at 22:14)</a>:</h4>
<p>I'm guessing your statement means one of these features provides it...</p>



<a name="227038419"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038419" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jacob Lifshay <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038419">(Feb 19 2021 at 22:17)</a>:</h4>
<p>CMPXCHG16B does</p>



<a name="227038580"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038580" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038580">(Feb 19 2021 at 22:18)</a>:</h4>
<p>"atomic compare-and-exchange 16 bytes"</p>



<a name="227038679"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038679" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038679">(Feb 19 2021 at 22:19)</a>:</h4>
<p>Ah that'll do it</p>



<a name="227038845"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038845" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038845">(Feb 19 2021 at 22:20)</a>:</h4>
<p>rustc doesn't recognize all these feature names btw, these are from the GCC list so maybe there's a different name we should be using, or maybe rustc hasn't been taught about these names.</p>



<a name="227038899"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227038899" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227038899">(Feb 19 2021 at 22:21)</a>:</h4>
<p>( it should be roughly the same set of features across compilers, since inevitably you'll wind up using the same logic in any case. )</p>



<a name="227039632"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227039632" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Thom Chiovoloni <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227039632">(Feb 19 2021 at 22:27)</a>:</h4>
<p><span class="user-mention silent" data-user-id="312331">Caleb Zulawski</span> <a href="#narrow/stream/257879-project-portable-simd/topic/Target.20feature.20levels/near/227037917">said</a>:</p>
<blockquote>
<p>Never even thought of that, do any architectures actually have 128-bit atomics or do they all need fences?</p>
</blockquote>
<p>x86_64-v2 and itanium both have it. it's helpful for implementing lockfree algorithms (the traditional example is a lockfree stack) without pointer tagging or complicated reclamation algorithms.</p>



<a name="227040765"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227040765" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227040765">(Feb 19 2021 at 22:37)</a>:</h4>
<p>Yeah, I could also see using that to write two pointers at a time for insertion/removal in certain data structures</p>



<a name="227042410"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042410" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Thom Chiovoloni <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042410">(Feb 19 2021 at 22:54)</a>:</h4>
<p>a pointer and a counter often, but yeah</p>



<a name="227042588"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042588" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042588">(Feb 19 2021 at 22:55)</a>:</h4>
<p>too bad that vec isn't defined as 2 pointers wide instead of 3 pointers</p>



<a name="227042766"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042766" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042766">(Feb 19 2021 at 22:57)</a>:</h4>
<p>...what's the third pointer width for?</p>



<a name="227042787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042787">(Feb 19 2021 at 22:57)</a>:</h4>
<p>pointer, length, capacity</p>



<a name="227042845"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042845" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042845">(Feb 19 2021 at 22:58)</a>:</h4>
<p>I know, it's upsetting.</p>



<a name="227042899"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042899" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042899">(Feb 19 2021 at 22:58)</a>:</h4>
<p>Oh forgot completely that length and capacity are separate.  It's the same in C++. Makes some things very efficient</p>



<a name="227042913"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227042913" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Thom Chiovoloni <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227042913">(Feb 19 2021 at 22:58)</a>:</h4>
<p>I've often lamented that <code>Box&lt;str&gt;</code> wasnt used over String, since then you could turn a <code>&amp;[Box&lt;str&gt;]</code> into a <code>&amp;[&amp;str]</code> 0 cost, whereas <code>&amp;[String]</code> =&gt; <code>&amp;[&amp;str]</code> is not zero cost. Anyway, this is getting pretty off topic.</p>



<a name="227043000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227043000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227043000">(Feb 19 2021 at 22:59)</a>:</h4>
<p><span class="user-mention" data-user-id="312331">@Caleb Zulawski</span> okay but do you really usually need to know both length and capacity without following the pointer, or would one be adequate and then storing the other at the pointer landing?</p>



<a name="227043240"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227043240" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227043240">(Feb 19 2021 at 23:01)</a>:</h4>
<p>Cache locality!</p>



<a name="227043350"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227043350" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227043350">(Feb 19 2021 at 23:02)</a>:</h4>
<p>yeah but if it was 16 bytes it would fit in an xmm register <span aria-label="weary" class="emoji emoji-1f629" role="img" title="weary">:weary:</span></p>



<a name="227049080"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227049080" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227049080">(Feb 20 2021 at 00:06)</a>:</h4>
<p>I can imagine ways to store it in 16 bytes, if we accepted a few limitations.</p>



<a name="227049186"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227049186" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227049186">(Feb 20 2021 at 00:07)</a>:</h4>
<p>For instance, if we limited the capacity to be representable in an ARM-style immediate encoding.</p>



<a name="227049213"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227049213" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227049213">(Feb 20 2021 at 00:07)</a>:</h4>
<p>VecButNotTooMany&lt;T&gt;</p>



<a name="227049230"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227049230" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227049230">(Feb 20 2021 at 00:07)</a>:</h4>
<p>More like "VecButNotTooPreciselyDifferentFromAPowerOfTwo".</p>



<a name="227052257"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227052257" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227052257">(Feb 20 2021 at 00:48)</a>:</h4>
<p>that's amazing.</p>



<a name="227052534"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227052534" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227052534">(Feb 20 2021 at 00:52)</a>:</h4>
<p>also I should note that generally size increasing algorithms for Vec or Vec-like things either use 2^N or  something roughly equivalent to *1.5</p>



<a name="227052863"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227052863" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227052863">(Feb 20 2021 at 00:56)</a>:</h4>
<p>so like<br>
that would actually very much work, probably. <span aria-label="eyes" class="emoji emoji-1f440" role="img" title="eyes">:eyes:</span></p>



<a name="227053016"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227053016" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227053016">(Feb 20 2021 at 00:58)</a>:</h4>
<blockquote>
<p>Most fundamentally, Vec is and always will be a (pointer, capacity, length) triplet. No more, no less. The order of these fields is completely unspecified, and you should use the appropriate methods to modify these. The pointer will never be null, so this type is null-pointer-optimized.</p>
</blockquote>
<p>hmm.</p>



<a name="227053633"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227053633" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227053633">(Feb 20 2021 at 01:07)</a>:</h4>
<p>Thank you for reminding me to finish writing my copy-free growing implementation of Vec using mmap</p>



<a name="227060375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060375">(Feb 20 2021 at 03:05)</a>:</h4>
<p>someone just please make a CopyKeyHashMap it would be so handy</p>



<a name="227060457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060457">(Feb 20 2021 at 03:06)</a>:</h4>
<p><span class="user-mention" data-user-id="224471">@Lokathor</span> a what</p>



<a name="227060478"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060478" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060478">(Feb 20 2021 at 03:07)</a>:</h4>
<p>A HashMap but the key must always be Copy so you never need to sometimes pass it by reference and sometimes pass it owned</p>



<a name="227060488"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060488" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060488">(Feb 20 2021 at 03:07)</a>:</h4>
<p>ahh</p>



<a name="227060490"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060490" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060490">(Feb 20 2021 at 03:07)</a>:</h4>
<p>think of how much simpler life could be for us all</p>



<a name="227060545"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060545" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060545">(Feb 20 2021 at 03:08)</a>:</h4>
<p>I feel like that can just be a wrapper over HashMap</p>



<a name="227060656"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060656" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060656">(Feb 20 2021 at 03:10)</a>:</h4>
<p>quite possibly yes</p>



<a name="227060665"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227060665" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227060665">(Feb 20 2021 at 03:10)</a>:</h4>
<p>could even Deref into a hashmap much of the time</p>



<a name="227112305"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Target%20feature%20level%20chatter/near/227112305" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Target.20feature.20level.20chatter.html#227112305">(Feb 20 2021 at 19:30)</a>:</h4>
<p>This is part of why I complained that Vec isn't 16 bytes, btw: <a href="https://github.com/rust-lang/rust/issues/35093">https://github.com/rust-lang/rust/issues/35093</a></p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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